LAND USE/LAND COVER CHANGE AND ORGANIC CARBON STOCK POTENTIAL UNDER DIFFERENT LAND MANAGEMENT SCENARIOS IN SIRARO WOREDA, CENTRAL RIFT VALLEY OF ETHIOPIA

Land degradation and climate change is the global challenge, where their impact is profoundly seen in developing countries including our country (Woolf et al., 2018). The Ethiopian Productive Safety Net Program (PSNP) is one of the national climate smart initiatives (CSI) implemented to address the persistent land degradation and climate challenges in the country. However, the PSNP effect on Land Use Land Cover (LULC) changes and its carbon storage potential is not yet studied at landscape levels. Thus, examining the effect of PSNP land management and providing accurate information are critically needed to guide land management policy in the face of climate change. Therefore, the present study aimed to assess land use/land cover change between 2001 and 2021 and carbon stock potential of PSNP and Non – PSNP areas in Siraro Woreda. Two proximate Kebeles, one with PSNP intervention and the other Non –PSNP sites were identified during reconnaissance survey and used to compare LULC changes and organic carbon stock potential in the study area. Remote sensing Landsat imageries, QGIS 3.2.3 version, and SCP tool used to examine LULC changes from (2001 – 2011), (2001 – 2021) and (2011 – 2021) in the study area. Both PSNP and Non – PSNP sites, stratified into agricultural and woodland for field data collection. Systematic random sampling method was used to locate sampling plots under each land use type along transect lines. The total of 80 sample plots, 40 m*50 m and 50 m*100 m plot sizes were used to inventor vegetation parameters in woodland and agricultural lands, respectively. Besides, the total of 160 composite soil samples were collected at two soil depths (0-20 cm, and 20-40 cm) from the corner and the center of the main plot and taken into Holeta Agricultural research Center for soil lab analysis and determination of soil organic carbon stock across the studied landscape site. The LULC change result revealed that agricultural land was converted to woodland by 539.67 ha (124.99%) under PSNP site, and continuously increased by 193.68 ha under Non –PSNP site between 2011 and 2021. Land management system, land use type and soil depth have significant effect (p ≤ 0.05) on organic carbon stock. PSNP land management system has contributed the largest biomass production (73.01Mg ha -) biomass carbon stock (51.11Mg C ha -) and soil organic carbon stock in the topsoil (62.67Mg C ha -) was recorded under woodland than agricultural land when compared to the results found under Non –PSNP site. The highest total carbon stock (1900.35 Mg C ha -) were observed in the PSNP site while the lowest total carbon stock (1473.57 Mg C ha -) found under Non – PSNP site. The total carbon stock difference (1280.34Mg C ha -) has shown the positive effect of PSNP land management interventions against Non – PSNP site (business as usual scenario). In conclusion, PSNP based land management plays a significant role for improving environmental management and climate change mitigation through carbon sequestration.